Method for cooling the heating coils of an oil-cracking apparatus



Aug. 20, 1929. G. EGLOFF ET AL METHOD FOR COOLING THE HEATING COILS OFAN OIL" CRACKING APPARATUS Original Filed March 23, 1921 Patented Aug.20, 1929.

UNITED STATES 1,725,067 PATENT OFFICE.

GUSTAV EGLOFI AND HARRY P. BENNER, OF CHICAGO, ILLINOIS, ASSIGNOBS TOUNIVERSAL OIL PRODUCTS COMPANY, F CHICAGO, ILLINOIS, A CORPORATION OFSOUTH DAKOTA.

METHOD FOR COOLING THE HEATING COILS OF AN OIL-CBACXING APPARATUS.

Original application led March 23, 1921, Serial No. 454,848. Divided andthis application tied January 14,

1925. Serial No. 2,384.

This invention relates to a method for cooling an apparatus for treatinghydrocarbon oils and is a division of our co-pending vapplication iledMarch 23, 1921, Serial N o.

454,848 which has eventuated into Patent N o.

1,541,553. The invention refers more particularly to that type ofconstruction in which the oil is fed through a heating coil, thencedelivered to an expansion chamber where vad through the entireapparatus. This 'takes time and also results in the oil being sentthrough a considerable part of the apparatus which is unnecessary. Afterthat, 1t 1s sometimes necessary to clean the gases out of parts of thesystem by steam or otherwise and more particularly out of the expansionchamber where vaporization takes place and the uncondensable gas hasbeen liberated. Time, vin the operation of cracking plants, particularlywhere there are a'large number of stills, is a matter of veryconsiderable im. portance from a commercial standpoint.

The object of the present invention is to provide a method for quicklycooling down the heating coils whereby they may be examined and cleanedof carbon and likewise the expansion chamber.

The appara-tus in which this is accomplished is shown in theaccompanying draw- 'ing in which the single li ure is a view, partly inside elevation, an partly in vertical section, of o'ur improvedapparatus.

Referring in detail to the drawing, 1 designates the furnace in which ismounted the heating coil 2 Which-may take the form of a continuous coilof say, 4-inch pipe. The inlet side of thecoil is connected by feed pi e3 to the charging pump 4 connected by tlie line 4 to the storage tank18. The discharge side of the coil is connected b the line 6 in which isinterposed a thrott e valve 5, to the expansion chamber 7 This chamber 7is provided with a vaporl outlet pipe 8, controlled by a throttle valve8, extending up into a horizontally disposed dephlegmator 5 9 having thealternately disposed battles 10. Vapor pipes 11 having throttle valve 12are provided for conducting the va`pors out of the dephlcgmator tocondenser coil 13. Condenser .coil 13 is connected by line 14s 6' havingthrottle valve 14 to the top of receiver 15. This receiver 15 isprovided with suitable pressure gauge and liquid level gauge as shown,and with gas outlet pipe 15 having throttle valve as shown, anddistillate drawoli' pipe 15" having a suitable throttle valve as shown.The reflux condensate is returned from the dephlegmator to the heatingcoil by means of the pipe 16 having throttle valve 17. The discharge ortransfer line 6 is 0 provided with a branch 19 having throttle valve 20leading back to the upper end of the receptacle 18. A throttle valve 21is in terposed in the line 4 and throttle valve 22 is provided in theline 3. Steam ma be introduced to the vapor or expansion c amber throughthe pipe 23 controlled by throttle valve 24 and ma be drawn olf throughthe pipe 26 having throttle valve 25.

The apparatus may be operated as follows: Oil may be introduced throu hthe feed/line 3 into the heating coil 2 and cated to a. temperature ofsay, 800 degrees F. in the transfer line and delivered in substantiallyliquid phase to the expansion chamber where vaporization takes place. Inthis case, the valves 5 and 8 are open. Valves 20 and 24 are closed. Thevapors pass out-of the pipe 8 into the dephleginator 9 where the heavierportions are condensed and returned 0 as reiux condensate through thelino 16 to the heating coil 2. The uncondensed vapors pass out ot' thepiple 11 through the condenser and thence to t e receiver. A pressure ofabout 140 pounds may be maintained on g5 the entire system, as for examle, in the treatment of a mid-continent fue oil.

After the system has been run for a more or less extended period oftime, carbon is bound to accumulate in the vapor chamber and there islikely to be a tendenc for some little carbon to be precipitated in theheating coil. Before cleanin out the heating coil it 1s necessary tocoo? down the system and this generally takes a considerable period oftime, which time, of course, is lost as far as use of the apparatus isconcerned. However,

We have devised a very simple and eective method and means ofaccomplishing this. To this end We close the valves 5 and 17 open thevalve 20 and circulate the cool oil through the closed circuit formed bythe tank 18, coil 2 and pipes 4 and 19. This orms a relatively shortcirculation but is nevertheless very effective in cooling the lsystem.At the same time, the valve 8 may be closed and steam injected throughthe pipe 23 under sulticient pressure to clean out the gases and cooldown the expansion chamber.

As another novel feature of the invention, We provide means forpreventing the carbon which is precipitated in the expansion chamberfrom piling up around the draw-off line and thus retarding the dischargeot the residuum. This is accomplished by means of a segmental haiheplate 27 which is mounted in the expansion chamber near the draw-oit 26and is segmental in orm so as to lit close- 1y around the lower sideWalls of the drum and may be of the height shown in the drawing. I

We claim as our invention:

1. A method for cooling the heating coil of a coil and chamber oilcracking apparatus of the character in which oil is continuouslysupplied to the heating coil, raised to a cracking temperature therein,and thence delivered to e chamber and which includes pipe amper yconnections for cyclically circulating oil from the bulk supply to theheating coil and back to the bulk supply comprising discontinuing theapplication of heat to the heating coil, ceasing the delivery of oilfrom the coil' to the chamber, continuing the passage oz? cool oilthrough the coil, returning the oil subsequent to its passage throughthe coil to a bulk supply of cool oil, -from which supply oil is beingdelivered to the coil until the coil is sufficiently cooled.

2. A method for cooling the heating coil of a tube and drum oil crackingapparatus of the character in which oil is continuously passed throughthe heating coil, raised to a cracking temperature therein, and thencedelivered to the reaction drum and which includes pipe connections forcyclically circulating oil from 'the bulk sup ly to the heating coil andback to the bulli supply, comprising discontinuing the application ofheat to the coil while continuing the passage of lcharging oil throughthe coil, returning the charging oil which has passed through the coilto. a source of cool oilsupply without admitting the same to said drum,and in continuing the supplyof oil romsaid source of supply to the coiluntil the temperature of the coil has been suiiiciently reduced.

GUSTAV EGLOFF. HARRY P. BENNER.

